Andrea Popova
I measured my hormones daily for 365 days:
This is what I learned about periods.
I’m Andrea, a Data Analyst at Meta with a background in obsessing over health and wellness. After years of struggling with irregular periods, I did what no one I know has done and measured my hormones every day for a year.
The results might surprise you.
Cultural Context
Birth Control
It would be difficult to overstate the positive impact that hormonal birth control has had on women’s lives and the US economy. When “the pill” was approved in the ‘60s, women had– for the first time ever– an almost 99% effective and discreet form of independence over their reproductive status. Not only has the impact been felt on an individual level, but increased birth control use is also linked to overall GDP growth as women are able to stay in the workforce longer than they otherwise would. And perhaps most interestingly, some research shows that the legalization of better contraceptive technology leads to a decline in crime. In other words, everybody wins.
But has there been a hidden cost?
Today about 24% of reproductive aged women in the United States use hormonal contraceptives (including “the pill,” implants, and hormonal IUDs), but that number may be decreasing. According to Google Trends the search term “side effects of stopping the pill after prolonged use” showed an increase of 350% in 2024. And when theSkimm polled its Instagram followers in the fall of 2023, 32% said they had recently stopped taking the birth control pill.
One reason could be that, what once felt like a form of liberation, now serves as yet another reminder of the burden women have to claim in order to maintain the status quo. Side effects from hormonal birth control are common and can be debilitating. The last several decades, and especially the #MeToo movement in 2016, have led women to wonder: why is male birth control medication still so far behind? And when it finally arrives… what will be the expectation for which gender carries the weight?
Another, and perhaps more pressing, reason for the decline in hormonal birth control use is a general trend towards natural, more holistic wellness. There is clear and disturbing evidence that hormonal disorders and hormone-based cancers are increasingly common and that factors in our environment are to blame. And while the direct impact of birth control on these trends is still up for discussion, some evidence continues to surface. For example, in several studies, the pill was linked to an increased risk in breast and cervical cancer. And in 2024 the hormonal contraceptive shot Depo-Provera faced and lost a class-action lawsuit after it was found to be linked to an increased risk in a benign but still negatively impactful type of brain tumor.
To avoid the risk of fear mongering, I would be remiss not to mention how hormonal birth control has also been linked to a decreased prevalence of some types of cancers including ovarian, endometrial, and colorectal cancer. Additionally, most of the negative outcomes that have been found are from more invasive and high dose birth controls, which have become less common in favor of locally-acting IUDs. But the overall long term impact of hormonal birth control has not been fully elucidated– probably because of the many benefits that we see as a society from its continued use.
With such limited information on these long term potential risks, many women have ditched medicated birth control and instead resorted to doing what’s worked for thousands of years– tracking their natural cycles. Unfortunately for us, we’ve spent so much time focusing on how to construct an unnatural cycle to prevent pregnancy, that we now lack the connection to our own bodies to understand… what even is a “natural” cycle?
The regularity of irregularity
My Diagnosis
What if, like 25% of reproductive women, you have an irregular cycle– one that does not consistently follow a 30 day resolution? I myself went to one of New York’s best Endocrinologists last year to try to understand why my cycles were never the same duration: ranging from 30 to 90 days between periods. The only consistent thing for my cycles is no consistency.
While it may seem convenient to have fewer periods, this condition is hardly a free ride. For starters, not knowing when to anticipate my period means that every time it starts I can almost guarantee bleeding through whatever I’m wearing. And secondly, the hormonal imbalance at the root is likely the main cause behind my persistent, lifelong acne and potentially other things I may not even be aware of. In short, it‘s annoying at best and negatively impacting my long term health at worst.
After running some bloodwork and ultrasounds, it was determined that I, like 13% of women, had PCOS (polycystic ovarian syndrome)-- which really just means “your periods are irregular and we don’t know why.” Usually PCOS patients have cysts all over their ovaries, I didn’t. It seems PCOS is just a catch-all for these mysterious imbalances.
When I asked which of my hormones was imbalanced (Estrogen? Progesterone?) or what part of my cycle was being drawn out (Follicular? Luteal?) the doctor sighed and said they couldn’t really determine without measuring my hormones every day of my cycle– something they would never do.
When I asked what I could do to regulate my hormones she shrugged and said “perhaps birth control?”
Doing it myself
Propelled by the lack of education, rampant catch-all diagnoses, and my own limited understanding of what was happening inside my body, I decided to take matters into my own hands. I found an at-home urine test I could use to measure my 3 key reproductive hormones every single day (by a brand called Inito). It’s marketed to women trying to get pregnant but that didn’t stop me.
And so I did what nobody I know has done before– I measured my hormones every single day* for 365 days. An entire year of period cycle data. And what I learned really shocked me…
*Every day except for the 14 day period when I was very ill with COVID. I actually have been measuring my hormones for almost 2 years now but this is a one year selection.
The Data
This 365 day view of my hormones looks chaotic at first glance…
But as we isolate the pieces we start to see a clearer picture…
Let’s take a look at just LH (luteinizing hormone) and Progesterone, two of the main hormones involved in fertility. I’ve added pink bars to signify when my period started each cycle.
Notice any patterns?
In every cycle, there is a consistent spike in LH near the end, followed by a spike in Progesterone which drops right before my period starts. It goes LH -> Progesterone -> period– every time. Even in cycles where LH didn’t have quite as dramatic of a spike, there is still clearly one.
This is expected. A spike in LH usually signifies the onset of (potential) ovulation– the 2-3 day window in which a woman is most likely to conceive– but the LH spike alone is not enough to confirm that ovulation occurred. Many women experience what is called an anovulatory cycle (where your LH spikes but your progesterone never does). Progesterone is triggered by LH in order to thicken the uterine lining to create an ideal environment for a fertilized egg to implant. Without it, conception cannot occur. You know those ovulation test strips you can buy at the drug store? They only measure LH (not progesterone) and they only compare your LH levels to the average LH surge numbers. So, if you naturally have higher than average LH (aka your baseline is higher) or if you don’t produce progesterone after your LH spike then those test results will not be a meaningful indicator of fertility.
Not only was I relieved to find that I ovulated during every cycle that I tracked, but I was also ecstatic to find something I never expected from this research— regularity.
You can’t tell from the chart itself, so here’s a table. Do you notice something?
I didn’t notice it at first either, but when I did it hit me like a ton of bricks. Though my cycles varied widely in duration overall, one thing was consistent— the time between each LH spike and period starting is consistently 14-16 days. So no matter when my cycle starts, I can always count on LH being about a 2 week warning for my next period.
This was groundbreaking for me. After feeling for years like there was no rhyme, rhythm or reason to my cycles, I finally found a sequence of events I could predictably track. After I first realized the pattern, I still wasn’t sure so I used the learning to predict my period for the first time. I was prepared for what I thought might come later that day. And I was right— I couldn’t believe my eyes. 45 days since my last period, “right on time,” it was there.
It seems once ovulation is initiated, then the rest of the cycle runs predictably. So reviewing this data I realized– perhaps the key to a shorter cycle is getting to ovulation sooner. In other words, shortening my late follicular phase. Here’s a crash course on period cycle phases:
For a “normal” 30-ish day cycle, ovulation occurs about 15 days from our period start date. The phase that seems to prepare the body for ovulation is the late follicular phase. During this phase, something must happen to trigger an LH surge at day 15. This something is a complex system of cascading events that can be crudely simplified as:
Estrogen spikes just before ovulation
These elevated estrogen levels from the ovaries trigger the hypothalamus
The hypothalamus secretes GnRH in a pulsatile fashion, which triggers LH to be released from the anterior pituitary
The LH spike must be high enough to then trigger ovulation. Otherwise the body will continue attempting to trigger an LH spike.
With my goal now focused on streamlining this process, I took a look at what happened during the follicular phase of two of my cycles: one that lasted 64 days, and another that lasted 32 days (almost “perfect”!).
It’s clear from the 32 day cycle what’s “supposed” to happen. Estrogen spiked at the end of the late follicular phase, driving a spike in LH, which then drove the remainder of ovulation. In the 64 day cycle, the pattern is less clear. It does seem the estrogen still had a clear spike at the end of the late follicular phase, but there were also some smaller peaks in estrogen in the days prior.
In the 64 day cycle, estrogen and LH danced back and forth, spiking just slightly then dropping, again and again, almost in tandem. Trying to determine the cause of this chicken-and-egg situation, I considered that my estrogen might have generally been too high (caused by some other chain of events). But comparing to the 32 day cycle, I’m not convinced high estrogen is the root cause of the issue here. Average estrogen in the follicular phase does not differ almost at all between the two cycles:
Instead, it appears that LH starts and stays higher in the follicular phase of the 64 day cycle than it does in the 32 day cycle. In fact it seems that generally LH levels are inversely related to cycle duration.
Taking a look at this chart of only LH over the last 365 days, where the distance between bars is the cycle duration, you can see that the two shortest cycles in the middle-right had the lowest LH spikes by far.
Not only were the LH spikes lowest for the shortest cycles, but so were their overall average LH levels. With a couple of outliers, it appears there is some correlation between average LH during the cycle and duration of the cycle:
It became clearer and clearer that lowering my baseline LH is a major key in shortening my cycle duration. This was further corroborated by the fact that one of the blood tests from my endocrinology visit actually showed slightly elevated blood sugar levels, indicating prediabetes (a very common indicator of mild insulin resistance that 1 in 3 Americans shows). In fact many studies have shown an intimate link between LH and insulin– so much so that insulin resistance is one of the most common outcomes (or causes?) of PCOS (the diagnosis I was given for my irregular periods).
When the body is more resistant to insulin, insulin levels rise in the blood. Insulin plays a vital role in stimulating LH activity, so the rise in insulin in turn drives elevated LH. This chain of events is so clear that for some people with PCOS, low dose insulin lowering medication (similar to the ones given to diabetes patients) can significantly improve regularity.
Today about 40% of Americans are insulin resistant, a number that is actually double what it was in the past 30 years and may double again in the next 20. There are various medications to treat insulin resistance, but for mild cases lifestyle changes can be very effective as a treatment. These changes include things like increasing exercise and following a keto (high protein, low carb) diet.
In addition to insulin resistance, I’ve spent a great deal of time conjuring other hypotheses behind my irregular periods. One of the more creative ones was that my irregularity is seasonal.
I noticed that my two shortest cycles occurred as the weather was getting warmer. From some research I learned that in fact sunlight exposure increases vitamin D synthesis, which helps the body produce insulin and regulate blood sugar. Some experts even recommend that people at risk of diabetes spend 30 minutes a day in the sun.
Although that theory was quickly dampened by a 68 day cycle in July, I still believe there could have been some truth to it. Years ago I asked my OBGYN why I had irregular periods (this was after a 3 month stretch without one– my longest ever). She smiled and said “a lot of things have to go right to have a period.” Conversely, this means that a lot of things can go wrong to stop a period. So even with all the sun in the world, something can still mess with the process. A natural cycle that so many take for granted is actually such a complex chain of reactions.
This chain is incredibly sensitive to change, and no factor is ever the only one at play. This is proven by the fact that, even after all this research and making some lifestyle changes, I really haven’t been able to fully regulate my cycle. And though I didn’t accomplish what I set out to do with this work, I still consider the learnings a massive success. I hope this data can serve as a guide for others trying to understand their cycles better. For a process that feels so out of our control, knowledge really can be power.
I also hope that this analysis highlights the potential downstream implications that come from overprescribing birth control. If I had simply taken hormonal birth control to regulate my cycle, my underlying insulin resistance may never have been explored or addressed. Furthermore, some hormonal birth controls – specifically estrogen-acting– can even exacerbate insulin resistance as they lead to increased blood glucose levels. For this reason, extra consideration is taken when prescribing hormonal birth control to diabetic women.
Tracking my natural cycle has helped me connect so much more deeply to my body and its intricacies. Ailments like acne or cramping that once felt like unwelcome visitors showing themselves at the most random moments now feel like an important piece in the natural flow of things. I also feel comforted by the data points showing how my hormones are working overtime in some cases to maintain homeostasis– like seeing my estrogen spike when I’m sick and knowing that my body is simply initiating an immune response due to estrogen’s powerful ability to slow down viral replication.
I’m so deeply grateful for products like Inito that are paving the way for modern cycle tracking, and hope this story can empower others to connect with their bodies, heal underlying issues, and reclaim agency over their reproductive decisions.